1. Field of the Invention
The present invention relates to an image forming system and a latent image carrier replacement time detection method which detect information of a latent image carrier replacement time useful in maintenance and analysis of an image forming apparatus including a latent image carrier, such as a photoconductor.
2. Description of the Related Art
An electrophotographic image forming apparatus forms an image by, for example, causing a charging device to uniformly charge a surface of a photoconductor serving as a latent image carrier to a predetermined potential, causing an exposure device to expose the charged surface of the photoconductor with light to form an electrostatic latent image, causing a development device to develop the electrostatic latent image on the surface of the photoconductor with toner to form a toner image, and transferring the toner image onto a recording medium. The photoconductor is replaced with a new photoconductor periodically or in the event of an unexpected failure, for example. Information concerning a photoconductor replacement time at which the photoconductor is replaced with a new photoconductor is useful in predicting the time of the next periodical replacement of the photoconductor.
Further, physical properties of the photoconductor and other components immediately before the replacement of the photoconductor may be used to detect the respective states of the photoconductor and the components at the time of failure or degradation, and are useful in, for example, analysis for failure prediction and design of a next-generation model. To obtain such physical properties, it is necessary to know the photoconductor replacement time, and in this regard also the photoconductor replacement time is useful information. Herein, the physical properties of the photoconductor include photoconductor potential, such as the potential of a latent image portion on the surface of the photoconductor (i.e., post-exposure potential), the potential of a non-latent image portion on the surface (i.e., uniform charge potential), and residual potential (i.e., post-discharge photoconductor surface potential).
The photoconductor replacement time may be detected from a maintenance date and time and a total count recorded in a maintenance work report in photoconductor replacement. Such information, however, is manually recorded, and thus an input error or an input omission may occur in the recording. It is therefore difficult to highly accurately detect the photoconductor replacement time.
The image forming apparatus may be controlled by a method which registers, in a storage medium, replacement history information including identification information of a replacement target component, such as a photoconductor, input to the image forming apparatus, and which, upon replacement of the replacement target component, adds the identification information of the replacement target component newly input to the replacement history information stored in the storage medium. The replacement history information includes the date of actual replacement of the component. The method, therefore, is capable of detecting the photoconductor replacement time with reference to the replacement history information.
According to this method, however, the replacement history information is manually input, and thus an input error or an input omission may occur similarly as in the foregoing method of recording the maintenance work report. It is therefore difficult to highly accurately detect the photoconductor replacement time.
Alternatively, the image forming apparatus may be provided with a sensor for detecting the installation of a photoconductor in the image forming apparatus, and may determine, upon detection of the installation of a photoconductor, that photoconductor replacement has taken place, and record the photoconductor replacement history information.
According to this method, the photoconductor replacement history information is recorded on the basis of the detection result of the sensor which detects the installation of a photoconductor. The method does not involve manual work, and thus is capable of detecting the photoconductor replacement time by ruling out human error. According to the method, however, if the photoconductor is removed from the image forming apparatus and reinstalled therein immediately thereafter, for example, it is determined that photoconductor replacement has taken place, with no distinction made between reinstallation of the non-new photoconductor and installation of a new photoconductor. It is therefore difficult to highly accurately detect the photoconductor replacement time at which the non-new photoconductor is replaced with a new photoconductor.
Accordingly, a new expendable item (e.g., photoconductor) may be provided with an identification chip indicating that the item is new, and the image forming apparatus installed with the new expendable item may detect the replacement of the expendable item with the use of the identification chip, and store the replacement time of the expendable item on the basis of the detection result. In this case, the image forming apparatus includes a device that removes the new item identification chip after the replacement of the expendable item is detected. If a non-new expendable item is installed in the image forming apparatus, therefore, the expendable item is not erroneously identified as a new expendable item, and the photoconductor replacement time is highly accurately detected.
According to this method, the photoconductor replacement is detected with the use of the new item identification chip provided to the photoconductor. The method is therefore capable of detecting the replacement time of a new photoconductor by ruling out human error and distinguishing the replacement of a new photoconductor from the reinstallation of a non-new photoconductor. Accordingly, the photoconductor replacement time at which a non-new photoconductor is replaced with a new photoconductor is highly accurately detected.
According to the method, however, a new item identification chip is provided to the photoconductor, and the device for removing the identification chip after the installation of a new photoconductor into the image forming apparatus is provided to the image forming apparatus. The method, therefore, increases component cost and manufacturing cost.